Cold Air Sump ram air filter box

[Carl Froehlich]

I’m installing a Thunderbolt CAS on the new RV-10 project, using the new James RV-10 cowl for this engine.

I would appreciate any air filter ideas from those using this engine. I’m familiar with the ShowPlanes cowl induction system, but this will not work with the James Cowl and plenum. I looked at the Rod Bower’s system but decided that is not applicable as I want filter full time.

Thanks,
Carl

 

[Richard Connell]

Hi Carl
I built a forward facing filter box for a large rectangular K&N filter to ram air straight into my FM300 on a CAS and showplanes cowl. I shamelessly copied DanH’s design and methodology.
Ultimately after rough fitting it I decided it was going to be rather unattractive to say the least (because it sits quite low and forward) and glassed the cowl up again and reverted to the SP induction.
I’ve got pictures. It’s not DanH quality so it’ll add no value to most and I’m embarrassed to post. PM me and I can send you some.
Cheers

 

[Carl Froehlich]

Krea/Richard

I agree, a flat air filter box along the lines of the expert (Dan Horton) would be the way to go, and I may just do that. Bill Harrelson (Lancair IV around the world guy) is my neighbor at VA42 so if I get stuck in fiberglass/carbon stuff perhaps he will be able to dig me out.

Jimmy at James Cowl has this as one of his projects, but considering the demand for his products I suspect it might take a long time to bubble to the top of his list.

Reading about Dan’s attempts at a conical filter (like the legacy James MK-3/MK-4) leads me to think that filter will support a 200HP engine but may fall short of supporting the CAS IO-540. I have this filter assembly in hand and Dan at AirFlow Performance has offered to flow test it for me. Real data is always preferred for such decisions.

The first RV-10 build (vertical induction James Cowl) performed well for me. This is the main reason why I’m sticking with the modified for CAS James Cowl on this final build.

On the IO-540 plenum, I used that on the first RV-10 and it came out well. For this build I offered Jimmy that I would use the stock Van’s RV-10 baffle kit and modify the plenum to fit. Once done I’d send that plenum back to Jimmy so he can make a mold and produce plenums that are more like bolt on parts that RV-14 builders like, but for RV-10 builders.

The new build is about at the “loose your religion” cabin top phase, and I’m still waiting for the engine from Thunderbolt (ordered over two years ago). I suspect I’ll get the engine and all the remaining kit back order stuff on the same day and will be swamped…..

Carl

 

[DanH]

Thank you for your kind comments, but really, there are no deep secrets in the airbox I've been flying the last 13 years.

I first built a sexy looking internal diffusion airbox for a conical filter. When Don Rivera put it on his Superflow, it was found to have a lot of pressure drop across the filter.

The general issue with the cone filters is a lack of pleat depth, in particular at the small end, i.e. if you cut the media off the molded ends and spread it out flat, it would not be very big.

So, I went back and looked at the flat filters with 7/8" deep pleats across the entire body. To fit a really large one (K&N 33-2124), I extended the airbox back under the FM-200. To avoid separation losses inside the inlet due to steep diverging angles, I went to a low Vi/Vo inlet (4" ring) for mostly external diffusion.

On the Superflow at 1440 PPH with a standard entry bell, the airbox and filter loss was only 1.9" H20, as compared to the FM-200 and entry bell alone.
.

 

[Bicyclops]

I used this one to make a filtered ram air inlet for my 6:
https://www.knfilters.com/e-0995-replacement-air-filter

It has 7/8 deep pleats and more surface area than Van's snorkel filter.

Ed

 

[Carl Froehlich]

Ed,

That is the one I have in hand. I’ll let you know how it flow tests.

Carl

 

[Bicyclops]

Ed,

That is the one I have in hand. I’ll let you know how it flow tests.

Carl

Interested to hear.

Ed

 

[DanH]

Interested to hear.

Me too.

How will you do alternate air?

 

[bob888]

Has anyone taken over supplying the Rod Bower system
?

 

[Carl Froehlich]

How will you do alternate air?

It will be a “swing into the filter box” door on a control cable - but details will wait pending filter shape and size selection.

Carl

 

[Bicyclops]

It will be a “swing into the filter box” door on a control cable - but details will wait pending filter shape and size selection.

Carl

That's what I did, though mine is swing out. I made a very hokey fiberglass box (my very first fiberglass project and not up to Dan H. standards by a wide margin ;-) ) with an extension on one side for the alternate air door. I used a piece of silicone cowl seal material as hinge/seal. Uugly but functional.

Ed

 

[Carl Froehlich]

That's what I did, though mine is swing out. I made a very hokey fiberglass box (my very first fiberglass project and not up to Dan H. standards by a wide margin ;-) ) with an extension on one side for the alternate air door. I used a piece of silicone cowl seal material as hinge/seal. Uugly but functional.

Ed

Just be careful to use pro-seal or such over fasteners so stuff does not work loose and get sucked into the engine.

Carl

 

[karrelsj]

I ended up building a box around a K&N flat filter that had a curve in it to match the curve of the cowl. The back side of that airbox has space for an alt air door. Then I built a "scoop" for looks. It probably doesn't meet any of the aerodynamic calculations, but I based it off one of the cool 300 Extra designs.